Promise for new anti-smoking therapy with 'Pac-Man' bacteria

Although there is still a way to go, a team working on a new type of anti-smoking therapy based on a bacterial enzyme that devours nicotine before it can reach
the brain are hopeful of success.

Researchers hope their anti-smoking enzyme therapy will offer a more successful alternative to current smoking cessation aids.

In the Journal of the American Chemical Society, scientists from The Scripps
Research Institute (TSRI) in La Jolla, CA, report how the enzyme can be made in the lab
and has a number of features that make it a promising candidate for drug
development.

Kim Janda, senior author and professor of chemistry, says:

"Our research is in the early phase of drug development process, but the
study tells us the enzyme has the right properties to eventually become a successful
therapeutic."

Prof. Janda and his team have been trying to create such an enzyme in the lab for
over 30 years.

But it was not until they turned to nature that they found what they were looking for
- a bacterium isolated from the soil of a tobacco field that consumes nicotine as its
only source of carbon and nitrogen.

'Eats nicotine like Pac-Man'

The bacterium - called Pseudomonas putida - relies on an enzyme called NicA2
to help it chomp away at nicotine, "like a little Pac-Man," Prof. Janda says.

The team's idea is to create an anti-smoking enzyme therapy that offers a more
successful alternative to current smoking cessation aids, which they note fail in at
least 80-90% of smokers.

The enzyme therapy would seek out and destroy nicotine before it reaches the
brain, thus preventing the "reward" kick that the addictive substance
gives.

In their paper, the Prof. Janda and colleagues describe how they analyzed the enzyme
and tested its potential as an anti-smoking therapy.

One feature that makes the enzyme attractive is from the tests they ran; the
researchers found it appears able to significantly reduce the time nicotine persists in
the bloodstream.

To show this, they combined serum (a component of blood) from mice with an amount of
nicotine that is equivalent to one cigarette. When they added the enzyme, instead of
taking 2-3 hours for the nicotine level to halve, it took only 9-15 minutes.

Prof. Janda says with a few chemical modifications, they could make a version
of the enzyme that would reduce the half-life of nicotine in the blood to the point
where it does not even reach the brain.

Enzyme is stable and has no detectable toxic byproducts

The team also ran several tests to find out how well the enzyme stood up as a drug
candidate and found the results encouraging.

The enzyme remained stable in the lab for over 3 weeks at 98 °F (37 °C) and showed no
detectable toxic byproducts when it degraded the nicotine. They found it is also
relatively stable in serum.

There is still some work to do to improve the enzyme's potential as a drug candidate,
note the researchers. For instance, they need to remove traces of its bacterial origin
to reduce the chance of it triggering an immune reaction. First author and TSRI graduate
student Song Xue says:

"Hopefully we can improve its serum stability with our future studies so
that a single injection may last up to a month."

Meanwhile, from another recently published study, Medical News Today also
learned that even if you have no willpower,
mindfulness meditation may help you quit smoking. The
researchers who came to this conclusion say mindfulness meditation helps to reduce
smoking by improving the brain's self-control network and moderating stress-reactivity.

Recommended related news

A new strategy for smoking cessation: characterization of a bacterial enzyme for the
degradation of nicotine, Song Xue et al., Journal of the American Chemical
Society, doi:10.1021/jacs.5b06605, published online 3 August 2015, abstract.

This story's speculation that a bacterial enzyme from a Pseudomonas species can actually treat nicotine dependence is frankly ridiculous. Not only is the administration of an enzyme derived from a bacteria fraught with technically challenging and possibly impossible barriers, but the effort put into such a frivolous treatment when clearly we should just quit smoking and ban cigarettes.

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